"While we were aware of Kurt's image being used with two Nirvana songs, we didn't know players have the ability to unlock the character," they said in a joint statement Thursday. "This feature allows the character to be used with any kind of song the player wants. We urge Activision to do the right thing in 're-locking' Kurt's character so that this won't continue in the future."

In an official statement, Activision, says Love signed a written agreement that gave them licensing rights to use Cobain's likeness for an playable character avatar.

The game, which includes 85 songs, features two Nirvana songs "Smells Like Teen Spirit" and "Lithium," but now Cobain can sing songs such as Bon Jovi's "You Give Love A Bad Name" and Megadeath's "Sweating Bullets."

Love has already expressed her thoughts to the media and on Twitter. In one tweet, she called Guitar Hero 5 "vile," and asked fans to call her lawyer and publicist with complaints. In another tweet, she wrote, "welcome to my NIGHTMARE. yeah well sue activision this is disgusting, but theres alot MORE."

"Ms. Cobain is extremely upset about Activision's use of Mr. Cobain's likeness to sing the songs of others in its Guitar Hero game," Mr. Fink told Kotaku. "Activision was granted permission by Kurt's trust solely to use his name and likeness. Activision was not given an unbridled right to use Mr. Cobain's name and likeness. Kurt's songs have a special and unique meaning to his fans and his image and legacy are very important to Ms. Cobain. The agreement Activision has with the trust doesn't allow them to use his likeness in ways that denigrate his image. We would hope Activision would do the right thing on its own and prohibit game users from using Kurt's image to sing others songs and if they don't we expect the trust to take appropriate action to protect Mr. Cobain's image."

A video of Kurt Cobain rapping and singing "You Give Love A Bad Name" has already surfaced on YouTube.

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